An overall three-dimensional workstation based photolithography simulator has been presented, that accounts for all of the three lithography subprocesses of mask imaging, resist exposure/bleaching and resist development. The imaging simulation relies on a vector-valued reformulation of the classical scalar theory of Fourier optics. The source discretization algorithm is especially adjusted to ensure an efficient exposure simulation under partial coherent illumination. A semi-analytical method to calculate the Fourier coefficients of the mask transmission function is proposed, that avoids any aliasing errors due to sampling of the non band-limited mask transmission function. The exposure/bleaching module extends the two-dimensional differential method to the third dimension. This novel three-dimensional extension was shown to be extremely efficient for the simulation of nonplanar scattering effects in combination with partial coherent illumination. For the development/etching step a cellular based topography simulator was adapted for lithography specific requirements such as rapid varying inhomogeneous etch rates. The capability of the overall simulator was demonstrated by showing simulation results of contact hole printing over a planar and a stepped substrate.